I currently have a fixed rate mortgage on my house with 24 years left until it is paid off. I won't mention the bank name that I make my payments to, but it is a large publicly traded bank. I usually pay my mortage a few months in advance, and then the bank immediately sends me a bill after I make a payment. For the second time in the last several months, they processed my mortgage payment incorrectly. Instead of applying it as a regular payment with some going to interest and some going to principal, they processed both payments as going to principal only, which means if I didn't call their customer service wondering where my next bill was, I would have been late on both payments, and assessed a late fee. I don't know if they are doing it deliberately to try to get me to pay a late fee, not that I would, or if their processors are just morons. Can I sue if it keeps happening? It reminds me of a story that I heard in the past when some credit card company would shred their customer's checks and then charge them a late fee for not sending in their payment.